Changes

| launch site = Le Grand Elementary School, Le Grand, CA

| launch site = Le Grand Elementary School, Le Grand, CA

| launch coordinates = 37.226, -120.251

| launch coordinates = 37.226, -120.251

| flight duration =  

| flight duration = 3h:52m

| flight length =  

| flight length = unknown

| flight profile = Ballast and vent control

| flight profile = Ballast and vent control

| landing time =  

| landing time =June 1, 2019, 14:27 ODT

| landing site=  

| landing site= 13 km SW of Mendota, Fresno County, CA

| landing coordinates =  

| landing coordinates = 36.692, -120.518

| last = 86

| last = 86

| next = 90

| next = 90

'''SSI-87''' (project designation '''CY-3''') was the third launch of [[Cycloon|Project Cycloon]] on June 1, 2019. It featured a legacy ballast and vent mechanism from ValBal operated by Cycloon avionics and was the first such fully controlled Cycloon flight. The mission was noted for its eventful manual equilibration, early termination, and for being the last latex Cycloon before the project transitioned to polyethylene. The payload was recovered the afternoon of the launch.

'''SSI-87''' (project designation '''CY-3''') was the third launch of [[Cycloon|Project Cycloon]] on June 1, 2019. It featured a legacy ballast and vent mechanism from ValBal operated by Cycloon avionics and was the first such fully controlled Cycloon flight. The mission was noted for its eventful manual equilibration, early termination, and for being the last latex Cycloon before the project transitioned to polyethylene. The payload was recovered the afternoon of the launch.

==Project context==

==Project context==

Before and around the time of the previous flight, CY-2, a reevaluation of project goals for the quarter had been underway. While a full apex vent equipped flight had originally been envisioned for the weekend of '''June 2''', delays on the project prompted a decision to focus more on quick iterations and numerous launches rather than awaiting longer term initiatives. In particular, it was decided that a legacy ValBal vent mechanism, while unlikely to suffice as a long-term solution, was sufficient and necessary for building altitude control expertise within Cycloon in the short term. Therefore, on '''May 19''', the day after CY-2, it was decided that two payloads would be launched on '''June 1''', alongside Spaceshot and onboarding, each with ballast, vent, and (winds permitting) tether and floater mechanism.

Before and around the time of the previous flight, CY-2, a reevaluation of project goals for the quarter had been underway. While a full apex vent equipped flight had originally been envisioned for the weekend of '''June 2''', delays on the project prompted a decision to focus more on quick iterations and numerous launches rather than awaiting longer term initiatives. In particular, it was decided that a legacy ValBal vent mechanism, while unlikely to suffice as a long-term solution, was sufficient and necessary for building altitude control expertise within Cycloon in the short term. Therefore, on '''May 19''', the day after CY-2, it was decided that two payloads would be launched on '''June 1''', alongside Spaceshot and onboarding, each with ballast, vent, and (winds permitting) tether and floater mechanism.

The bulk of the avionics work for the two payloads occurred on May 27, and first demonstration of vent motor control was achieved on May 29. The bulk of the mechanics work occurred that same day, although due to a lack of spare mechanics the second payload was cancelled. Due to favorable wind forecasts, a floater was confirmed. Substantial mechanical integration was finalized on May 31, the day before the launch.

The bulk of the avionics work for the two payloads was completed on May 27, followed by demonstration of vent control on May 29. As winds forecasts for favorable for a float-drop profile, a floater was confirmed for the final configuration. The bulk of the mechanics work occurred on May 29, though due to a lack of spare mechanics the second payload was cancelled. Finally, substantial system integration occurred on May 31. It was hoped that the flight would land safely in the Pacific, enabling controlled daytime hops throughout the following week.

==Configuration==

==Configuration==

==Flight synopsis==

==Flight synopsis==

'''June 1, 2019, 1035 PDT:''' Launch. A fitting between the neck of the balloon and the vent had to be improvised on site. The target ascent rate was 1.7 - 2 m/s, and the flight plan was to equilibrate at 19-22km, with the first vents occurring at 14km.

'''June 1, 2019, 1035 PDT:''' Launch. A fitting between the neck of the balloon and the vent had to be improvised on site. The target ascent rate was 1.7 - 2 m/s, and the flight plan was to equilibrate at 19-22km, with the first vents occurring at 14km.

'''June 1, 2019, 1355 PDT:''' To play it safe, yet 96 more seconds were sent, as the balloon was nearing the danger zone. Following this, a slight descent was observed after a peak altitude of 22.100 km, and equilibration was declared.

'''June 1, 2019, 1355 PDT:''' To play it safe, yet 96 more seconds were sent, as the balloon was nearing the danger zone. Following this, a slight descent was observed after a peak altitude of 22.100 km, and equilibration was declared.

'''June 1, 2019, 1409 PDT:''' It was noticed that the GPS coordinates and altitude had frozen at the launch site. The cause for this remains unknown, and hence no detailed trajectory of this flight is available. Simulatenously, the barometer began reporting a negative altitude. This is when the balloon probably popped, after spending only three communication intervals between 22.0 and 22.1 km.

'''June 1, 2019, 1409 PDT:''' It was noticed that the GPS coordinates and altitude had frozen at the launch site. The cause for this remains unknown, and hence no detailed trajectory of this flight is available. Simultaneously, the barometer began reporting a negative altitude. This is when the balloon probably popped, after spending only three communication intervals between 22.0 and 22.1 km.

'''June 1, 2019, 1427 PDT:''' Iridium triangulation began reporting consistent coordinates. It is believed that this was payload impact.

'''June 1, 2019, 1427 PDT:''' Iridium triangulation began reporting consistent coordinates. It is believed that this was payload impact.

'''June 1, 2019, 1435 PDT:''' GPS began reporting coordinates of landing site. It remains unknown why this reset occurred. A recovery team was dispatched to the landing site.

'''June 1, 2019, 1435 PDT:''' GPS began reporting coordinates of landing site. It remains unknown why this reset occurred. A recovery team was dispatched to the landing site.

 

{{balloon-footer}}

{{balloon-footer}}

[[Category: High Altitude Balloons]][[Category: Balloon Launches]]

[[Category: High Altitude Balloons]][[Category: Balloon Launches]]